The present invention relates to a cooling device for semiconductor modules.
Semiconductor modules such as IGBTs, GTOs, IGCTs tend toward ever higher switching capacities or blocking voltages and forward currents, and are operated primarily in the pulse control operation of self-commutated converters like, for example, a pulse-controlled inverter, at increasingly higher switching frequencies. However, since the switching losses are essentially a function of these quantities, it is necessary to resort to suitable measures for cooling the modules, in order to carry away as efficiently as possible the dissipation power arising.
Present liquid-cooled pulse-controlled inverters have a base plate, through which a cooling medium flows, and the power semiconductors are mounted on it, for example, by screwing on, clamping or cementing. The power semiconductor modules are usually cooled on the lower side, where as a rule they have a flat, metallic surface. To improve the thermal tie between this lower side and the upper side of the actively cooled base plate which is likewise as flat as possible, heat-conductive paste, heat-conductive foil or heat-conductive adhesive agent is partially used. To provide the best possible thermal contact between the heat source (switching element) and the heat sink (base plate traversed by flow), the switching elements are often pressed with great force on the base plate. The limited thermal conductivity of these materials represents the greatest thermal resistance in the heat path from the power semiconductor to the cooling medium. The expenditure for assembly is considerable because of the introduction, for example, of the heat-conductive paste between the semiconductor module and the base plate, and the necessary pressure connection of the module to the plate.
Compared to the known design approach, the cooling device of the present invention for semiconductor modules has the advantage that the thermal properties of, in particular, actively cooled semiconductor modules are improved, and in addition, a simpler, more compact and more cost-effective construction, particularly of pulse-controlled inverters, is made possible.
The idea underlying the present invention is based essentially on the use of a cooler bar in connection with actively cooled high-current modules, instead of a cooled base plate with power semiconductors to be cooled in a planar fashion.
In the present invention, the problem mentioned at the outset is solved in particular in that a cooler bar accommodates at least one semiconductor module and has a plurality of bore holes or channels for conducting a, in particular, liquid coolant to and from the semiconductor module, through which the coolant flows directly.
According to one preferred refinement, the coolant is able to be supplied to or conducted away from at least two semiconductor modules in parallel via supply channels and/or return channels of the cooler bar. This brings the advantage of being able to cool units having a plurality of modules concurrently.
According to a further preferred refinement, the coolant is able to be supplied to or carried away from at least two semiconductor modules in series via supply channels and/or return channels, the coolant being able to be conducted via the cooler bar from one semiconductor module to an additionally mounted semiconductor module. This brings the advantage of being able to cool units having a plurality of modules sequentially.
In a further preferred embodiment, the cooler bar essentially has a metal, particularly aluminum, with the advantage that the bar is easy to process and possesses good thermal conductivity.
According to a further preferred development, the cooler bar has at least one fixing device for securing one or more semiconductor modules, from which are yielded advantageous securing possibilities.
In another preferred refinement, the device has a sealing element, particularly O-rings, for sealing between the channels of the cooler bar and the semiconductor module(s), to ensure an advantageous leakage-free interface.
In a further preferred refinement, the, in particular, liquid coolant essentially has water or demineralized water. This brings the advantage that the coolant can be handled easily and without problems, as well as low costs.
In a further preferred development, the cooler bar essentially forms a support structure, by which the semiconductor modules are able to be interconnected and/or the cooling device is able to be secured, it thereby being advantageously possible to dispense with additional support structures.
According to another preferred embodiment, the cooler bar has further components, such as structural elements, electric lines, sensors or a control, in order to utilize the advantage of a compact configuration.
In a further preferred refinement, the cooler bar has semiconductor modules on several sides of the cooler bar, in order to utilize the advantage of a compact configuration.
Exemplary embodiments of the present invention are represented in the drawing and are explained in greater detail in the following description.